[dev.regabi] cmd/compile/internal/gc: prep for Func.Nname removal refactoring

There are three bits of method-handling code where we separately go
from Field->Type and then Type->Node. By shuffling the code around a
little to go Field->Type->Node in a single statement, we're able to
more easily remove Type from the operation.

Passes toolstash-check.

Change-Id: Ife98216d70d3b867fa153449abef0e56a4fb242a
Reviewed-on: https://go-review.googlesource.com/c/go/+/272388
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

src/cmd/compile/internal/gc/bexport.go

@@ -12,6 +12,15 @@ type exporter struct {
 	marked map[*types.Type]bool // types already seen by markType
 }
 
+// markObject visits a reachable object.
+func (p *exporter) markObject(n *Node) {
+	if n.Op == ONAME && n.Class() == PFUNC {
+		inlFlood(n)
+	}
+
+	p.markType(n.Type)
+}
+
 // markType recursively visits types reachable from t to identify
 // functions whose inline bodies may be needed.
 func (p *exporter) markType(t *types.Type) {
@@ -28,7 +37,7 @@ func (p *exporter) markType(t *types.Type) {
 	if t.Sym != nil && t.Etype != TINTER {
 		for _, m := range t.Methods().Slice() {
 			if types.IsExported(m.Sym.Name) {
-				p.markType(m.Type)
+				p.markObject(asNode(m.Type.Nname()))
 			}
 		}
 	}
@@ -63,11 +72,6 @@ func (p *exporter) markType(t *types.Type) {
 		}
 
 	case TFUNC:
-		// If t is the type of a function or method, then
-		// t.Nname() is its ONAME. Mark its inline body and
-		// any recursively called functions for export.
-		inlFlood(asNode(t.Nname()))
-
 		for _, f := range t.Results().FieldSlice() {
 			p.markType(f.Type)
 		}

src/cmd/compile/internal/gc/dcl.go

@@ -824,7 +824,7 @@ func methodSymSuffix(recv *types.Type, msym *types.Sym, suffix string) *types.Sy
 // - msym is the method symbol
 // - t is function type (with receiver)
 // Returns a pointer to the existing or added Field; or nil if there's an error.
-func addmethod(msym *types.Sym, t *types.Type, local, nointerface bool) *types.Field {
+func addmethod(n *Node, msym *types.Sym, t *types.Type, local, nointerface bool) *types.Field {
 	if msym == nil {
 		Fatalf("no method symbol")
 	}
@@ -897,6 +897,7 @@ func addmethod(msym *types.Sym, t *types.Type, local, nointerface bool) *types.F
 	}
 
 	f := types.NewField(lineno, msym, t)
+	f.Type.SetNname(asTypesNode(n.Func.Nname))
 	f.SetNointerface(nointerface)
 
 	mt.Methods().Append(f)

src/cmd/compile/internal/gc/iexport.go

@@ -243,14 +243,13 @@ const (
 )
 
 func iexport(out *bufio.Writer) {
-	// Mark inline bodies that are reachable through exported types.
+	// Mark inline bodies that are reachable through exported objects.
 	// (Phase 0 of bexport.go.)
 	{
 		// TODO(mdempsky): Separate from bexport logic.
 		p := &exporter{marked: make(map[*types.Type]bool)}
 		for _, n := range exportlist {
-			sym := n.Sym
-			p.markType(asNode(sym.Def).Type)
+			p.markObject(n)
 		}
 	}
 

src/cmd/compile/internal/gc/iimport.go

@@ -327,19 +327,14 @@ func (r *importReader) doDecl(n *Node) {
 			recv := r.param()
 			mtyp := r.signature(recv)
 
-			ms[i] = types.NewField(mpos, msym, mtyp)
-
 			m := newfuncnamel(mpos, methodSym(recv.Type, msym))
 			m.Type = mtyp
 			m.SetClass(PFUNC)
 			// methodSym already marked m.Sym as a function.
 
-			// (comment from parser.go)
-			// inl.C's inlnode in on a dotmeth node expects to find the inlineable body as
-			// (dotmeth's type).Nname.Inl, and dotmeth's type has been pulled
-			// out by typecheck's lookdot as this $$.ttype. So by providing
-			// this back link here we avoid special casing there.
-			mtyp.SetNname(asTypesNode(m))
+			f := types.NewField(mpos, msym, mtyp)
+			f.Type.SetNname(asTypesNode(m))
+			ms[i] = f
 		}
 		t.Methods().Set(ms)
 

src/cmd/compile/internal/gc/typecheck.go

@@ -3412,7 +3412,7 @@ func typecheckfunc(n *Node) {
 	t.FuncType().Nname = asTypesNode(n.Func.Nname)
 	rcvr := t.Recv()
 	if rcvr != nil && n.Func.Shortname != nil {
-		m := addmethod(n.Func.Shortname, t, true, n.Func.Pragma&Nointerface != 0)
+		m := addmethod(n, n.Func.Shortname, t, true, n.Func.Pragma&Nointerface != 0)
 		if m == nil {
 			return
 		}